Michal Cizek/Agence France-Presse — Getty Images

Related

Half of an unusual tandem of power, Mr. Kaczynski was elected president in 2005 from the nationalist-conservative Law and Justice Party, led by his identical twin, Jaroslaw, whom he later appointed prime minister.

Swept into office as voters repudiated the group of former Communist officials who had dominated the country’s politics for much of the preceding decade, Mr. Kaczynski and his brother struggled at the top. They frequently put Poland on a collision course with its European Union partners and Russia, while polarizing voters at home with a shift to the right.

“His approach is to first destroy and then think about what to build,” Lech Walesa, hero of the Solidarity movement and former president, said in 2006 of Lech Kaczynski, who once served as Mr. Walesa’s national security chief.

Poland joined the European Union in 2004, but Mr. Kaczynski often preferred dealing with the United States.

As soon as Mr. Kaczynski took office in the presidential headquarters in the center of Warsaw, he forged close relations with Ukraine and Georgia, determined to bring them closer to NATO and eventually have them admitted to the American-led military organization.

His defense of those two countries often upset leading members of the European Union, especially Germany, which was concerned that an expanded NATO would make Russia feel threatened and lead to new East-West tensions. Mr. Kaczynski, however, believed passionately that a strong NATO would prevent Russia from reasserting its influence over Eastern and Central Europe.

Mr. Kaczynski was born on June 18, 1949, when Warsaw was in ruins. His suspicions of Russia and Germany had deep roots. His father, Rajmund, an engineer, and his mother, Jadwiga, who studied linguistics, had been active in the Polish resistance against the Nazis.

He and his brother — who could be told apart only by a mole on Lech’s left cheek — became famous at age 12 when they starred in a film version of “The Two Who Stole the Moon,” a beloved children’s story. They began their rise to political prominence in the underground Solidarity movement in the 1980s.

They were close, at first, to Mr. Walesa, but they fell out with his movement during the 1990s, claiming that the intellectuals, led by Adam Michnik, had made too many compromises with former Communists and the secret police. The brothers remained active in politics, with Lech Kaczynski serving as justice minister from 2000 to 2001 and gaining popularity by emphasizing his tough stance against crime.

He became mayor of Warsaw in 2002, and critics began to see his brand of nationalism — he and his brother wanted a complete break with the past by purging the civil service and the media of former Communists — as overzealous and provincial. But the twins were helped in their rise to power by an image of honesty in a country that had witnessed one corruption scandal after another for years.

Yet he was not reluctant to create tensions with Moscow or Berlin. Poland joined NATO in 1999, part of the first bloc of former Communist countries, along with Hungary and the Czech Republic, to join the alliance.

“It was obvious to us that this was the only tough security structure there was in the world, and that the membership of NATO would only mean benefits for Poland,” Mr. Kaczynski said in an interview last year.

He added that did not mean that Russia’s leaders had “abandoned their ideas to regain influence, like using natural resources, natural gas, as a weapon and trying to influence politicians.”

“Indeed,” he said, “back in the early 1990s, my impression was that Poland’s entry into NATO would finally resolve those questions. And here I must admit I was wrong.”

He lobbied hard for the United States to deploy part of its controversial shield against ballistic missiles in Poland, arguing that it would enhance Poland’s security against Russia. Those plans, supported by President George W. Bush, were scaled back by President Obama.

A devout Roman Catholic, Mr. Kaczynski was regarded as skeptical of the European Union while he fought to defend Poland’s sovereignty against Brussels and to protect its traditional, conservative values. In 2008, he argued against ratifying the union’s Lisbon Treaty for fear its prohibition of discrimination on the basis of sexual orientation would become Polish law.

Mr. Kaczynski’s star had been fading in recent years, and he would have faced a difficult re-election battle this year.

His wife, Maria, an economist, also died in the crash. Mr. Kaczynski is survived by his brother, Jaroslaw, who was forced to step down as prime minister in 2007 after a bruising party defeat at the polls. He is also survived by his daughter, Marta; two granddaughters, Ewa and Martyna; and his mother.

Correction: April 10, 2010

An earlier version of this obituary gave an incorrect age for Lech Kaczynski.